1. Field of the Invention.
This invention relates generally to the art of coating glass and more particularly to the art of depositing transparent, electroconductive coatings such as indium oxide by cathode sputtering.
2. The Prior Art
U.S. Pat. No. 3,907,660 to Gillery describes a method for cathode sputtering electroconductive films in a low pressure atmosphere of oxygen and an inert gas, preferably argon, in which the oxygen content of the mixture of gases is controlled within limits determined by the substrate temperature developed during the cathode sputtering operation. The partial pressure of oxygen in the low pressure atmosphere of the sputtering chamber is initially relatively high as the cathode sputtering begins and is reduced as the temperature of the substrate increases. During coating, the resistance of the deposited film is monitored continually. The oxygen concentration is varied to maintain a controlled rate of decrease in resistance of the deposited film. The above method relies heavily on the skill of the operator since too much oxygen can retard the rate of decrease in resistance while too little oxygen can result in an opaque metallic film.